When Brazil's president Dilma Rousseff arrives on the Côte d'Azur, she will bring harsh words for her European counterparts.

As the European debt crisis has dragged on, and concerns over the possible impacts on Brazil and other emerging economies have grown, Rousseff and her finance minister, Guido Mantega, have become increasingly vocal in their criticism of the European response. "The Europeans always take too long to find solutions," Mantega grumbled earlier this month. "And when they come they come late."

David Fleischer, a political scientist from the University of Brasilia, said the Brazilian delegation would not mince their words during the G20 meeting. "The Brazilian message will be: 'You have to get your game together and make some decisions,'" he said. "It's a pretty harsh line but the Europeans know they have to decide something."

Brazilian authorities insist they are well prepared for the consequences of an extended and deepening crisis in Europe, but growing fears of "contagion" have made policy makers around the developing world edgy, even in booming Brazil. "There is concern about contagion," Fleischer said. "European firms have been pulling their money out of Brazil and taking it home … The whole economy is slowing down."

Last year Brazil's economy grew 7.5%, its highest rate in nearly 25 years, but in August the projected growth rate for 2011 was cut to around 3.8% amid signs that China's economy was slowing.

Brazil's main fear is that the European debt crisis might yet deepen into a full-blown financial crisis that would send waves through the global economy, affecting China and in turn damaging the economies of emerging countries such as Brazil, which is heavily dependent on the Asian colossus to buy its iron ore and other commodities.

Recent reports of a fall in China's trade surplus did little to allay such concerns.

"There is the worry that the crisis will hit China, because China depends on global demand. If global demand falls below a certain level then the country will not have a way of exporting its products," Mantega admitted last week in Paris on the eve of the G20 meeting. "A reduction in China's growth will end up affecting the emerging [economies] which today are still relatively shielded from the Euro-American crisis."

"The emerging economies, which are more dynamic, have not so far been affected. But if the crisis deepens it will also impact on the emerging [economies] and we will suffer the consequences," Mantega said.

Antônio Carlos Lessa, an international relations professor from the University of Brasilia, said concern over "contagion" meant the Brazilians were likely to arrive in Cannes with all guns blazing.

Rousseff, he believed, was likely to "provoke" and "preach" to the rich nations – particularly the European powers and to a lesser extent the US. Rousseff would point out that Brazil had learned from past financial crises and that "rich countries should now do their homework" to stop their crisis contaminating other emerging economies, he said.

Lessa added, however, that such "provocations" were unlikely to help solve the current crisis. "It is one thing to say these things … But in a crisis of this complexity it is not Brazil provoking or condemning that is going to change things.

"The crisis is like a burst dam. First we need to stop the leak. Then we can find a way to rebuild it."

Whether Brazil is able to influence the outcome of the Cannes talks or not, Lessa said Brazil's leadership in uniting leaders from a variety of emerging economies towards a common position was a positive sign of the country's growing clout and reach on the global stage.

"For the first time Brazil has made a strong effort to coordinate positions [between emerging economies]," Lessa said, pointing to a recent Ibsa (India, Brazil and South Africa) summit in Pretoria at which a common position for the G20 summit was negotiated, and in talks with Mexico and Argentina.

"Brazil now sees itself in a position to express these concerns," on behalf of other emerging nations, he said. "Brazil will confirm its position as a mediator between rich and poor countries."